U.S. patent application number 17/035192 was filed with the patent office on 2021-12-30 for methods for producing high-density, nitrogen-doped carbon films for hardmasks and other patterning applications.
The applicant listed for this patent is Applied Materials, Inc.. Invention is credited to Jui-Yuan HSU, Karthik JANAKIRAMAN, Pramit MANNA.
Application Number | 20210407791 17/035192 |
Document ID | / |
Family ID | 1000005241039 |
Filed Date | 2021-12-30 |
United States Patent
Application |
20210407791 |
Kind Code |
A1 |
HSU; Jui-Yuan ; et
al. |
December 30, 2021 |
METHODS FOR PRODUCING HIGH-DENSITY, NITROGEN-DOPED CARBON FILMS FOR
HARDMASKS AND OTHER PATTERNING APPLICATIONS
Abstract
Embodiments of the present disclosure generally relate to the
fabrication of integrated circuits. More particularly, the
embodiments described herein provide techniques for depositing
nitrogen-doped diamond-like carbon films for patterning
applications. In one or more embodiments, a method for processing a
substrate includes flowing a deposition gas containing a
hydrocarbon compound and a nitrogen dopant compound into a
processing volume of a process chamber having a substrate
positioned on an electrostatic chuck, and generating a plasma at or
above the substrate by applying a first RF bias to the
electrostatic chuck to deposit a nitrogen-doped diamond-like carbon
film on the substrate. The nitrogen-doped diamond-like carbon film
has a density of greater than 1.5 g/cc and a compressive stress of
about -20 MPa to less than -600 MPa.
Inventors: |
HSU; Jui-Yuan; (Santa Clara,
CA) ; MANNA; Pramit; (Santa Clara, CA) ;
JANAKIRAMAN; Karthik; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
1000005241039 |
Appl. No.: |
17/035192 |
Filed: |
September 28, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16915110 |
Jun 29, 2020 |
|
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17035192 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/02115 20130101;
C23C 16/272 20130101; H01L 21/0332 20130101; H01L 21/0337 20130101;
H01L 21/02274 20130101; H01L 21/02337 20130101 |
International
Class: |
H01L 21/02 20060101
H01L021/02; H01L 21/033 20060101 H01L021/033; C23C 16/27 20060101
C23C016/27 |
Claims
1. A method of processing a substrate, comprising: flowing a
deposition gas comprising a hydrocarbon compound and a nitrogen
dopant compound into a processing volume of a process chamber
having a substrate positioned on an electrostatic chuck; and
generating a plasma above the substrate by applying a first RF bias
to the electrostatic chuck to deposit a nitrogen-doped diamond-like
carbon film on the substrate, wherein the nitrogen-doped
diamond-like carbon film has a density of greater than 1.5 g/cc and
a compressive stress of about -20 MPa to less than -600 MPa.
2. The method of claim 1, wherein the nitrogen-doped diamond-like
carbon film has a compressive stress of about -250 MPa to about
-400 MPa.
3. The method of claim 1, wherein the nitrogen-doped diamond-like
carbon film has an elastic modulus of greater than 60 GPa to about
200 GPa.
4. The method of claim 1, wherein the nitrogen-doped diamond-like
carbon film has a density of about 1.55 g/cc to less than 2
g/cc.
5. The method of claim 1, wherein the nitrogen dopant compound
comprises dinitrogen (N.sub.2), atomic nitrogen, ammonia,
hydrazine, methylhydrazine, dimethlyhydrazine, t-butylhydrazine,
phenylhydrazine, azoisobutane, ethylazide, pyridine, derivatives
thereof, abducts thereof, or any combination thereof.
6. The method of claim 5, wherein the nitrogen dopant compound
comprises dinitrogen.
7. The method of claim 1, wherein the nitrogen dopant compound is
flowed into the processing volume at a rate of about 10 sccm to
about 1,000 sccm.
8. The method of claim 1, wherein the processing volume is
maintained at a pressure of about 0.5 mTorr to about 10 Torr when
generating the plasma and depositing the nitrogen-doped
diamond-like carbon film on the substrate.
9. The method of claim 8, wherein the processing volume is
maintained at a pressure of about 5 mTorr to about 100 mTorr, and
wherein the substrate is maintained at a temperature of about
0.degree. C. to about 50.degree. C.
10. The method of claim 1, wherein the nitrogen-doped diamond-like
carbon film comprises about 1 atomic percent to about 15 atomic
percent of nitrogen.
11. The method of claim 1, wherein the nitrogen-doped diamond-like
carbon film comprises about 50 atomic percent to about 90 atomic
percent of spa hybridized carbon atoms.
12. The method of claim 1, wherein the hydrocarbon compound
comprises ethyne, propene, methane, butene, 1,3-dimethyladamantane,
bicyclo[2.2.1]hepta-2,5-diene, adamantine, norbornene, or any
combination thereof.
13. The method of claim 1, wherein the deposition gas further
comprises helium, argon, xenon, neon, hydrogen (H.sub.2), or any
combination thereof.
14. The method of claim 1, wherein generating the plasma at the
substrate further comprises applying a second RF bias to the
electrostatic chuck.
15. The method of claim 14, wherein the electrostatic chuck has a
chucking electrode and an RF electrode separate from the chucking
electrode, and wherein the first RF bias is applied to the RF
electrode and the second RF bias is applied to the chucking
electrode.
16. The method of claim 14, wherein the first RF bias is provided
at a power of about 10 watts to about 3,000 watts at a frequency of
about 350 KHz to about 100 MHz, and wherein the second RF bias is
provided at a power of about 10 watts to about 3,000 watts at a
frequency of about 350 KHz to about 100 MHz.
17. A method of processing a substrate, comprising: flowing a
deposition gas comprising a hydrocarbon compound and a nitrogen
dopant compound into a processing volume of a process chamber
having a substrate positioned on an electrostatic chuck, wherein
the electrostatic chuck has a chucking electrode and an RF
electrode separate from the chucking electrode, and wherein the
processing volume is maintained at a pressure of about 0.5 mTorr to
about 10 Torr; and generating a plasma above the substrate by
applying a first RF bias to the RF electrode and a second RF bias
to the chucking electrode to deposit a nitrogen-doped diamond-like
carbon film on the substrate, wherein the nitrogen-doped
diamond-like carbon film comprises about 0.1 atomic percent to
about 20 atomic percent of nitrogen and about 50 atomic percent to
about 90 atomic percent of sp.sup.3 hybridized carbon atoms, and
has a density of greater than 1.5 g/cc and a compressive stress of
about -20 MPa to less than -600 MPa.
18. The method of claim 17, wherein the nitrogen-doped diamond-like
carbon film comprises about 55 atomic percent to about 75 atomic
percent of sp.sup.3 hybridized carbon atoms.
19. The method of claim 17, wherein the nitrogen-doped diamond-like
carbon film has a density of about 1.55 g/cc to less than 2 g/cc, a
compressive stress of about -250 MPa to about -400 MPa, and an
elastic modulus of greater than 60 GPa to about 200 GPa.
20. A method of processing a substrate, comprising: flowing a
deposition gas comprising a hydrocarbon compound and a nitrogen
dopant compound into a processing volume of a process chamber
having a substrate positioned on an electrostatic chuck, wherein
the electrostatic chuck has a chucking electrode and an RF
electrode separate from the chucking electrode, and wherein the
processing volume is maintained at a pressure of about 0.5 mTorr to
about 10 Torr; generating a plasma above the substrate by applying
a first RF bias to the RF electrode and a second RF bias to the
chucking electrode to deposit a nitrogen-doped diamond-like carbon
film on the substrate, wherein the nitrogen-doped diamond-like
carbon film comprises about 0.1 atomic percent to about 20 atomic
percent of nitrogen, and has a density of greater than 1.5 g/cc and
a compressive stress of about -20 MPa to less than -600 MPa;
forming a patterned photoresist layer over the nitrogen-doped
diamond-like carbon film; etching the nitrogen-doped diamond-like
carbon film in a pattern corresponding with the patterned
photoresist layer; and etching the pattern into the substrate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 16/915,110, filed Jun. 29, 2020, which is
herein incorporated by reference.
BACKGROUND
Field
[0002] Embodiments of the present disclosure generally relate to
the fabrication of integrated circuits. More particularly, the
embodiments described and discussed herein provide techniques for
the deposition of high-density films for patterning
applications.
Description of the Related Art
[0003] Integrated circuits have evolved into complex devices that
can include millions of transistors, capacitors and resistors on a
single chip. The evolution of chip designs continually requires
faster circuitry and greater circuit density. The demands for
faster circuits with greater circuit densities impose corresponding
demands on the materials used to fabricate such integrated
circuits. In particular, as the dimensions of integrated circuit
components reduce to the sub-micron scale, it is now necessary to
use low resistivity conductive materials as well as low dielectric
constant insulating materials to obtain suitable electrical
performance from such components.
[0004] The demands for greater integrated circuit densities also
impose demands on the process sequences used in the manufacture of
integrated circuit components. For example, in process sequences
that use conventional photolithographic techniques, a layer of
energy sensitive resist is formed over a stack of material layers
disposed on a substrate. The energy sensitive resist layer is
exposed to an image of a pattern to form a photoresist mask.
Thereafter, the mask pattern is transferred to one or more of the
material layers of the stack using an etch process. The chemical
etchant used in the etch process is selected to have a greater etch
selectivity for the material layers of the stack than for the mask
of energy sensitive resist. That is, the chemical etchant etches
the one or more layers of the material stack at a rate much faster
than the energy sensitive resist. The etch selectivity to the one
or more material layers of the stack over the resist prevents the
energy sensitive resist from being consumed prior to completion of
the pattern transfer.
[0005] As the pattern dimensions are reduced, the thickness of the
energy sensitive resist is correspondingly reduced in order to
control pattern resolution. Such thin resist layers can be
insufficient to mask underlying material layers during the pattern
transfer step due to attack by the chemical etchant. An
intermediate layer (e.g., silicon oxynitride, silicon carbine or
carbon film), called a hardmask, is often used between the energy
sensitive resist layer and the underlying material layers to
facilitate pattern transfer because of greater resistance to the
chemical etchant. Hardmask materials having both high etch
selectivity and high deposition rates are desirable. As critical
dimensions (CD) decrease, current hardmask materials lack the
desired etch selectivity relative to underlying materials (e.g.,
oxides and nitrides) and are often difficult to deposit.
[0006] Therefore, there is a need in the art for an improved
hardmask layers and methods for depositing improved hardmask
layers.
SUMMARY
[0007] Embodiments of the present disclosure generally relate to
the fabrication of integrated circuits. More particularly, the
embodiments described and discussed herein provide techniques for
the deposition of high-density films, such as nitrogen-doped
diamond-like carbon films, for patterning applications. In one or
more embodiments, a method of processing a substrate includes
flowing a deposition gas containing a hydrocarbon compound and a
nitrogen dopant compound into a processing volume of a process
chamber having a substrate positioned on an electrostatic chuck,
and generating a plasma at or above the substrate by applying a
first RF bias to the electrostatic chuck to deposit a
nitrogen-doped diamond-like carbon film on the substrate. The
nitrogen-doped diamond-like carbon film has a density of greater
than 1.5 g/cc and a compressive stress of about -20 MPa to less
than -600 MPa. In some examples, the nitrogen-doped diamond-like
carbon film has a density of greater than 1.5 g/cc to about 2.1
g/cc and a compressive stress of about -200 MPa to less than -600
MPa.
[0008] In some embodiments, a method of processing a substrate
includes flowing a deposition gas containing a hydrocarbon compound
and a nitrogen dopant compound into a processing volume of a
process chamber having a substrate positioned on an electrostatic
chuck, where the electrostatic chuck has a chucking electrode and
an RF electrode separate from the chucking electrode, and the
processing volume is maintained at a pressure of about 0.5 mTorr to
about 10 Torr. The method further includes generating a plasma
above the substrate by applying a first RF bias to the RF electrode
and a second RF bias to the chucking electrode to deposit a
nitrogen-doped diamond-like carbon film on the substrate. The
nitrogen-doped diamond-like carbon film contains about 0.1 atomic
percent to about 20 atomic percent of nitrogen and about 50 atomic
percent to about 90 atomic percent of spa hybridized carbon atoms,
and has a density of greater than 1.5 g/cc and a compressive stress
of about -20 MPa to less than -600 MPa.
[0009] In other embodiments, a method of processing a substrate
includes flowing a deposition gas containing a hydrocarbon compound
and a nitrogen dopant compound into a processing volume of a
process chamber having a substrate positioned on an electrostatic
chuck, where the electrostatic chuck has a chucking electrode and
an RF electrode separate from the chucking electrode, and the
processing volume is maintained at a pressure of about 0.5 mTorr to
about 10 Torr. The method also includes generating a plasma above
the substrate by applying a first RF bias to the RF electrode and a
second RF bias to the chucking electrode to deposit a
nitrogen-doped diamond-like carbon film on the substrate. The
nitrogen-doped diamond-like carbon film contains about 0.1 atomic
percent to about 20 atomic percent of nitrogen, and has a density
of greater than 1.5 g/cc and a compressive stress of about -20 MPa
to less than -600 MPa. The method further includes forming a
patterned photoresist layer over the nitrogen-doped diamond-like
carbon film, etching the nitrogen-doped diamond-like carbon film in
a pattern corresponding with the patterned photoresist layer, and
etching the pattern into the substrate.
[0010] In one or more embodiments, a nitrogen-doped diamond-like
carbon film for use as an underlayer for an extreme ultraviolet
("EUV") lithography process is provided and contains about 0.1
atomic percent to about 20 atomic percent of nitrogen and about 50
atomic percent to about 90 atomic percent or about 60 atomic
percent to about 70 atomic percent of spa hybridized carbon atoms.
The nitrogen-doped diamond-like carbon film has a density of
greater than 1.5 g/cc to about 2.1 g/cc, about 1.55 g/cc to less
than 2 g/cc, or about 1.6 g/cc to about 1.8 g/cc and a compressive
stress of about -20 MPa to less than -600 MPa, about -200 MPa to
about -500 MPa, or about -250 MPa to about -400 MPa.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] So that the manner in which the above recited features of
the disclosure can be understood in detail, a more particular
description of the disclosure, briefly summarized above, may be had
by reference to implementations, some of which are illustrated in
the appended drawings. It is to be noted, however, that the
appended drawings illustrate only typical implementations of this
disclosure and are therefore not to be considered limiting of
scope, for the disclosure may admit to other equally effective
implementations.
[0012] FIG. 1A depicts a schematic cross-sectional view of a
deposition system that can be used to practice processes according
to one or more embodiments described and discussed herein.
[0013] FIG. 1B depicts a schematic cross-sectional view of another
deposition system that can be used to practice processes according
to one or more embodiments described and discussed herein.
[0014] FIG. 2 depicts a schematic cross-sectional view of an
electrostatic chuck that may be used in the apparatus of FIGS.
1A-1B, according to one or more embodiments described and discussed
herein.
[0015] FIG. 3 depicts a flow diagram of a method for forming a
nitrogen-doped diamond-like carbon film on a film stack disposed on
a substrate according to one or more embodiments described and
discussed herein.
[0016] FIGS. 4A-4B depict a sequence for forming a nitrogen-doped
diamond-like carbon film on a film stack formed on a substrate
according to one or more embodiments described and discussed
herein.
[0017] FIG. 5 depicts a flow diagram of a method of using a
nitrogen-doped diamond-like carbon film according to one or more
embodiments described and discussed herein.
[0018] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
and features of one embodiment may be beneficially incorporated in
other embodiments without further recitation.
DETAILED DESCRIPTION
[0019] Embodiments provided herein relate to nitrogen-doped
diamond-like carbon films and methods for depositing or otherwise
forming the nitrogen-doped diamond-like carbon films on a
substrate. Certain details are set forth in the following
description and in FIGS. 1A-5 to provide a thorough understanding
of various embodiments of the disclosure. Other details describing
well-known structures and systems often associated with plasma
processing and diamond-like carbon film deposition are not set
forth in the following disclosure to avoid unnecessarily obscuring
the description of the various embodiments.
[0020] Many of the details, dimensions, angles and other features
shown in the Figures are merely illustrative of particular
embodiments. Accordingly, other embodiments can have other details,
components, dimensions, angles and features without departing from
the spirit or scope of the present disclosure. In addition, further
embodiments of the disclosure can be practiced without several of
the details described below.
[0021] Embodiments described herein, include improved methods of
fabricating nitrogen-doped diamond-like carbon films with
high-density (e.g., >1.5 g/cc), high elastic modulus (e.g.,
>60 GPa), and low compressive stress (e.g., <-500 MPa). The
nitrogen-doped diamond-like carbon films fabricated according to
the embodiments described herein are amorphous in nature and have a
greater etch selectivity along with lower stress than current
patterning films. The nitrogen-doped diamond-like carbon films
fabricated according to the embodiments described herein not only
have a low compressive stress but also have a high spa carbon
content. In general, the deposition process described herein is
also fully compatible with current integration schemes for hardmask
applications.
[0022] In one or more embodiments, the nitrogen-doped diamond-like
carbon films described herein may be formed by chemical vapor
deposition (CVD), such as plasma enhanced CVD and/or thermal CVD
processes, using a deposition gas containing one or more
hydrocarbon compounds and one or more nitrogen dopant compounds. In
one or more examples, a deposition gas containing one or more
hydrocarbon compounds, one or more nitrogen dopant compounds, and
optionally one or more dilution gases can be flowed or otherwise
introduced into a processing volume of a process chamber. A
substrate is positioned or otherwise disposed on an electrostatic
chuck within the processing volume, where the electrostatic chuck
has a chucking electrode and an RF electrode separate from the
chucking electrode. The method further includes generating a plasma
at and/or above the substrate by applying a first RF bias to the RF
electrode and a second RF bias to the chucking electrode to deposit
a nitrogen-doped diamond-like carbon film on the substrate.
[0023] Embodiments described and discussed herein will be discussed
in reference to a plasma-enhanced chemical vapor deposition
(PE-CVD) process that can be carried out using any suitable thin
film deposition system. Examples of suitable systems include the
CENTURA.RTM. systems which may use a DXZ.RTM. processing chamber,
PRECISION 5000.RTM. systems, PRODUCER.RTM. systems, PRODUCER.RTM.
GT.TM. systems, PRODUCER.RTM. XP Precision.TM. systems,
PRODUCER.RTM. SE.TM. systems, Sym3.RTM. processing chamber, and
Mesa.TM. processing chamber, all of which are commercially
available from Applied Materials, Inc., of Santa Clara, Calif.
Other tools capable of performing PE-CVD processes may also be
adapted to benefit from the embodiments described herein. In
addition, any system enabling the PE-CVD processes described herein
can be used to advantage. The apparatus description described
herein is illustrative and should not be construed or interpreted
as limiting the scope of the embodiments described herein.
[0024] Exemplary hydrocarbon compounds can be or include ethyne or
acetylene (C.sub.2H.sub.2), propene (C.sub.3H.sub.6), methane
(CH.sub.4), butene (C.sub.4H.sub.8), 1,3-dimethyladamantane,
bicyclo[2.2.1]hepta-2,5-diene (2,5-norbornadiene), adamantine
(C.sub.10H.sub.16), norbornene (C.sub.7H.sub.10), derivatives
thereof, isomers thereof, or any combination thereof. Exemplary
nitrogen dopant compounds can be or include dinitrogen (N.sub.2),
atomic nitrogen, ammonia, hydrazine, methylhydrazine,
dimethlyhydrazine, t-butylhydrazine, phenylhydrazine, azoisobutane,
ethylazide, pyridine, derivatives thereof, abducts thereof, or any
combination thereof. The deposition gas may further include one,
two, or more dilution gases, carrier gases, and/or purge gases,
such as, for example, helium, argon, xenon, neon, nitrogen
(N.sub.2), hydrogen (H.sub.2), or any combination thereof. In some
examples, the deposition gas may further include etchant gases such
as chlorine (Cl.sub.2), carbon tetrafluoride (CF.sub.4), and/or
nitrogen trifluoride (NF.sub.3) to improve film quality.
[0025] The substrate and/or the processing volume can be heated and
maintained at independent temperatures during the deposition
process. The substrate and/or the processing volume can be heated
to a temperature of about -50.degree. C., about -40.degree. C.,
about -25.degree. C., about -10.degree. C., about -5.degree. C.,
about 0.degree. C., about 5.degree. C., or about 10.degree. C. to
about 15.degree. C., about 20.degree. C., about 23.degree. C.,
about 30.degree. C., about 50.degree. C., about 100.degree. C.,
about 150.degree. C., about 200.degree. C., about 300.degree. C.,
about 400.degree. C., about 500.degree. C., or about 600.degree. C.
For example, the substrate and/or the processing volume can be
heated to a temperature of about -50.degree. C. to about
600.degree. C., about -50.degree. C. to about 450.degree. C., about
-50.degree. C. to about 350.degree. C., about -50.degree. C. to
about 200.degree. C., about -50.degree. C. to about 100.degree. C.,
about -50.degree. C. to about 50.degree. C., about -50.degree. C.
to about 0.degree. C., about -40.degree. C. to about 200.degree.
C., about -40.degree. C. to about 100.degree. C., about -40.degree.
C. to about 80.degree. C., about -40.degree. C. to about 50.degree.
C., about -40.degree. C. to about 25.degree. C., about -40.degree.
C. to about 10.degree. C., about -40.degree. C. to about 0.degree.
C., about 0.degree. C. to about 600.degree. C., about 0.degree. C.
to about 450.degree. C., about 0.degree. C. to about 350.degree.
C., about 0.degree. C. to about 200.degree. C., about 0.degree. C.
to about 120.degree. C., about 0.degree. C. to about 100.degree.
C., about 0.degree. C. to about 80.degree. C., about 0.degree. C.
to about 50.degree. C., about 0.degree. C. to about 25.degree. C.,
about 10.degree. C. to about 600.degree. C., about 10.degree. C. to
about 450.degree. C., about 10.degree. C. to about 350.degree. C.,
about 10.degree. C. to about 200.degree. C., about 10.degree. C. to
about 100.degree. C., or about 10.degree. C. to about 50.degree.
C.
[0026] The processing volume of the processing chamber is
maintained at sub-atmospheric pressures during the deposition
process. The processing volume of the processing chamber is
maintained at a pressure of about 0.1 mTorr, about 0.5 mTorr, about
1 mTorr, about 5 mTorr, about 10 mTorr, about 50 mTorr, or about 80
mTorr to about 100 mTorr, about 250 mTorr, about 500 mTorr, about 1
Torr, about 5 Torr, about 10 Torr, about 20 Torr, about 50 Torr, or
about 100 Torr. For example, the processing volume of the
processing chamber is maintained at a pressure of about 0.1 mTorr
to about 10 Torr, about 0.1 mTorr to about 5 Torr, about 0.1 mTorr
to about 1 Torr, about 0.1 mTorr to about 500 mTorr, about 0.1
mTorr to about 100 mTorr, about 0.1 mTorr to about 10 mTorr, about
1 mTorr to about 10 Torr, about 1 mTorr to about 5 Torr, about 1
mTorr to about 1 Torr, about 1 mTorr to about 500 mTorr, about 1
mTorr to about 100 mTorr, about 1 mTorr to about 10 mTorr, about 5
mTorr to about 10 Torr, about 5 mTorr to about 5 Torr, about 5
mTorr to about 1 Torr, about 5 mTorr to about 500 mTorr, about 5
mTorr to about 100 mTorr, or about 5 mTorr to about 10 mTorr. In
one or more examples, the processing volume is maintained at a
pressure of about 0.5 mTorr to about 10 Torr, about 1 mTorr to
about 500 mTorr, or about 5 mTorr to about 100 mTorr when
generating the plasma and depositing the nitrogen-doped
diamond-like carbon film on a substrate maintained at a temperature
of about 0.degree. C. to about 50.degree. C.
[0027] The plasma (e.g., capacitive-coupled plasma) may be formed
from either top and bottom electrodes or side electrodes. The
electrodes may be formed from a single powered electrode, dual
powered electrodes, or more electrodes with multiple frequencies
such as, but not limited to, about 350 KHz, about 2 MHz, about
13.56 MHz, about 27 MHz, about 40 MHz, about 60 MHz, and about 100
MHz, being used alternatively or simultaneously in a CVD system
with any or all of the reactant gases listed herein to deposit a
thin film of diamond-like carbon for use as a hardmask and/or etch
stop or any other application requiring smooth carbon films. The
high etch selectivity of the nitrogen-doped diamond-like carbon
film is achieved by having greater density and modulus than current
generation films. Not to be bound by theory but it is believed that
the greater density and modulus are a result of the high content of
spa hybridized carbon atoms in the nitrogen-doped diamond-like
carbon film, which in turn may be achieved by a combination of low
pressure and plasma power.
[0028] In one or more embodiments, the nitrogen-doped diamond-like
carbon film is deposited in a process chamber with the substrate
pedestal maintained at about 10.degree. C. and a pressure at about
2 mTorr, with plasma generated at or above the substrate level by
applying a bias of about 2,500 watts (about 13.56 MHz) to the
electrostatic chuck. In other embodiments, an additional RF of
about 1,000 watts at about 2 MHz is also delivered to the
electrostatic chuck thus generating a dual-bias plasma at the
substrate level.
[0029] In one or more embodiments, hydrogen radical are fed through
an RPS, which leads to selective etching of sp.sup.2 hybridized
carbon atoms thus increasing the sp.sup.3 hybridized carbon atom
fraction of the film further, thus further increasing the etch
selectivity. The nitrogen-doped diamond-like carbon film can have a
concentration or percentage of sp.sup.3 hybridized carbon atoms
(e.g., a sp.sup.3 hybridized carbon atom content) that is at least
40 atomic percent (at %), about 45 at %, about 50 at %, about 55 at
%, or about 58 at % to about 60 at %, about 65 at %, about 70 at %,
about 75 at %, about 80 at %, about 85 at %, about 88 at %, about
90 at %, about 92 at %, or about 95 at %, based on the total amount
of carbon atoms in the nitrogen-doped diamond-like carbon film. For
example, the nitrogen-doped diamond-like carbon film can have a
concentration or percentage of sp.sup.3 hybridized carbon atoms
that is at least 40 at % to about 95 at %, about 45 at % to about
95 at %, about 50 at % to about 95 at %, about 50 at % to about 90
at %, about 50 at % to about 85 at %, about 50 at % to about 80 at
%, about 50 at % to about 75 at %, about 50 at % to about 70 at %,
about 50 at % to about 65 at %, about 55 at % to about 75 at %,
about 55 at % to about 70 at %, about 55 at % to about 65 at %,
about 55 at % to about 60 at %, about 60 at % to about 80 at %,
about 60 at % to about 75 at %, about 60 at % to about 70 at %,
about 60 at % to about 65 at %, about 65 at % to about 95 at %,
about 65 at % to about 90 at %, about 65 at % to about 85 at %,
about 65 at % to about 80 at %, about 65 at % to about 75 at %,
about 65 at % to about 70 at %, about 65 at % to about 68 at %,
about 75 at % to about 95 at %, about 75 at % to about 90 at %,
about 75 at % to about 85 at %, about 75 at % to about 80 at %, or
about 75 at % to about 78 at %, based on the total amount of carbon
atoms in the nitrogen-doped diamond-like carbon film.
[0030] In some embodiments, the nitrogen-doped diamond-like carbon
film can have a concentration or percentage of sp.sup.2 hybridized
carbon atoms (e.g., a sp.sup.2 hybridized carbon atom content) that
is less than 60 at %, such as less than 55 at % or less than 50 at
%. The nitrogen-doped diamond-like carbon film can have a
concentration or percentage of sp.sup.2 hybridized carbon atoms
that is about 5 at %, about 10 at %, about 15 at %, about 20 at %,
about 25 at %, about 28 at %, or about 30 at % to about 32 at %,
about 35 at %, about 36 at %, about 38 at %, about 40 at %, about
45 at %, about 50 at %, about 55 at %, or about 60 at %, based on
the total amount of carbon atoms in the nitrogen-doped diamond-like
carbon film. For example, the nitrogen-doped diamond-like carbon
film can have a concentration or percentage of sp.sup.2 hybridized
carbon atoms that is about 5 at % to about 60 at %, about 5 at % to
about 50 at %, about 5 at % to about 45 at %, about 5 at % to about
40 at %, about 5 at % to about 38 at %, about 5 at % to about 36 at
%, about 5 at % to about 35 at %, about 5 at % to about 32 at %,
about 5 at % to about 30 at %, about 5 at % to about 25 at %, about
5 at % to about 20 at %, about 5 at % to about 15 at %, about 5 at
% to about 10 at %, about 20 at % to about 60 at %, about 20 at %
to about 50 at %, about 20 at % to about 45 at %, about 20 at % to
about 40 at %, about 20 at % to about 38 at %, about 20 at % to
about 36 at %, about 20 at % to about 35 at %, about 20 at % to
about 32 at %, about 20 at % to about 30 at %, about 20 at % to
about 25 at %, about 20 at % to about 22 at %, about 30 at % to
about 60 at %, about 30 at % to about 50 at %, about 30 at % to
about 45 at %, about 30 at % to about 40 at %, about 30 at % to
about 38 at %, about 30 at % to about 36 at %, about 30 at % to
about 35 at %, about 30 at % to about 32 at %, about 32 at % to
about 38 at %, about 32 at % to about 36 at %, about 32 at % to
about 34 at %, about 34 at % to about 38 at %, or about 34 at % to
about 36 at %, based on the total amount of carbon atoms in the
nitrogen-doped diamond-like carbon film.
[0031] A concentration or percentage of the nitrogen in the
nitrogen-doped diamond-like carbon film is about 0.01 at %, about
0.05 at %, about 0.1 at %, about 0.3 at %, about 0.5 at %, about
0.8 at %, about 1 at %, about 1.2 at %, about 1.5 at %, about 1.8
at %, about 2 at %, about 2.5 at %, or about 2.8 at % to about 3 at
%, about 3.5 at %, about 4 at %, about 5 at %, about 6 at %, about
7 at %, about 8 at %, about 9 at %, about 10 at %, about 12 at %,
about 15 at %, about 18 at %, about 20 at %, about 25 at %, about
30 at %, or greater, based on the total amount of atoms in the
nitrogen-doped diamond-like carbon film. For example, the
concentration or percentage of the nitrogen in the nitrogen-doped
diamond-like carbon film is about 0.01 at % to about 25 at %, about
0.1 at % to about 25 at %, about 0.5 at % to about 25 at %, about 1
at % to about 25 at %, about 2 at % to about 25 at %, about 3 at %
to about 25 at %, about 5 at % to about 25 at %, about 7 at % to
about 25 at %, about 10 at % to about 25 at %, about 12 at % to
about 25 at %, about 15 at % to about 25 at %, about 18 at % to
about 25 at %, about 20 at % to about 25 at %, about 0.1 at % to
about 20 at %, about 0.5 at % to about 20 at %, about 1 at % to
about 20 at %, about 2 at % to about 20 at %, about 3 at % to about
20 at %, about 5 at % to about 20 at %, about 7 at % to about 20 at
%, about 10 at % to about 20 at %, about 12 at % to about 20 at %,
about 15 at % to about 20 at %, about 18 at % to about 20 at %,
about 0.1 at % to about 18 at %, about 0.5 at % to about 18 at %,
about 1 at % to about 18 at %, about 2 at % to about 18 at %, about
3 at % to about 18 at %, about 5 at % to about 18 at %, about 7 at
% to about 18 at %, about 10 at % to about 18 at %, about 12 at %
to about 18 at %, about 15 at % to about 18 at %, about 0.1 at % to
about 15 at %, about 0.5 at % to about 15 at %, about 1 at % to
about 15 at %, about 2 at % to about 15 at %, about 3 at % to about
15 at %, about 5 at % to about 15 at %, about 7 at % to about 15 at
%, about 10 at % to about 15 at %, about 12 at % to about 15 at %,
about 0.01 at % to about 10 at %, about 0.1 at % to about 10 at %,
about 0.5 at % to about 10 at %, about 1 at % to about 10 at %,
about 2 at % to about 10 at %, about 3 at % to about 10 at %, about
4 at % to about 10 at %, about 5 at % to about 10 at %, about 7 at
% to about 10 at %, about 0.01 at % to about 5 at %, about 0.1 at %
to about 5 at %, about 0.5 at % to about 5 at %, about 1 at % to
about 5 at %, about 2 at % to about 5 at %, or about 3 at % to
about 5 at %, based on the total amount of atoms in the
nitrogen-doped diamond-like carbon film.
[0032] The nitrogen-doped diamond-like carbon film has a density of
greater than 1.5 g/cc (grams per cubic centimeter (cm.sup.3)), such
as about 1.55 g/cc, about 1.6 g/cc, about 1.65 g/cc, or about 1.68
g/cc to about 1.7 g/cc, about 1.72 g/cc, about 1.75 g/cc, about
1.78 g/cc, about 1.8 g/cc, about 1.85 g/cc, about 1.9 g/cc, about
1.95 g/cc, about 1.98 g/cc, about 2 g/cc, about 2.05 g/cc, about
2.1 g/cc, or greater. For example, the nitrogen-doped diamond-like
carbon film has a density of greater than 1.5 g/cc to about 2.1
g/cc, greater than 1.5 g/cc to about 2.05 g/cc, greater than 1.5
g/cc to about 2 g/cc, greater than 1.5 g/cc to about 1.9 g/cc,
greater than 1.5 g/cc to about 1.85 g/cc, greater than 1.5 g/cc to
about 1.8 g/cc, greater than 1.5 g/cc to about 1.78 g/cc, greater
than 1.5 g/cc to about 1.75 g/cc, greater than 1.5 g/cc to about
1.72 g/cc, greater than 1.5 g/cc to about 1.7 g/cc, greater than
1.5 g/cc to about 1.68 g/cc, greater than 1.5 g/cc to about 1.65
g/cc, greater than 1.5 g/cc to about 1.6 g/cc, about 1.6 g/cc to
about 2.1 g/cc, about 1.6 g/cc to about 2.05 g/cc, about 1.6 g/cc
to about 2 g/cc, about 1.6 g/cc to about 1.9 g/cc, about 1.6 g/cc
to about 1.85 g/cc, about 1.6 g/cc to about 1.8 g/cc, about 1.6
g/cc to about 1.78 g/cc, about 1.6 g/cc to about 1.75 g/cc, about
1.6 g/cc to about 1.72 g/cc, about 1.6 g/cc to about 1.7 g/cc,
about 1.6 g/cc to about 1.68 g/cc, about 1.6 g/cc to about 1.65
g/cc, about 1.68 g/cc to about 2.1 g/cc, about 1.68 g/cc to about
2.05 g/cc, about 1.68 g/cc to about 2 g/cc, about 1.68 g/cc to
about 1.9 g/cc, about 1.68 g/cc to about 1.85 g/cc, about 1.68 g/cc
to about 1.8 g/cc, about 1.68 g/cc to about 1.78 g/cc, about 1.68
g/cc to about 1.75 g/cc, about 1.68 g/cc to about 1.72 g/cc, about
1.68 g/cc to about 1.7 g/cc, about 1.7 g/cc to about 1.75 g/cc,
about 1.7 g/cc to about 1.72 g/cc, about 1.55 g/cc to less than 2
g/cc, about 1.6 g/cc to less than 2 g/cc, about 1.65 g/cc to less
than 2 g/cc, about 1.68 g/cc to less than 2 g/cc, about 1.7 g/cc to
less than 2 g/cc, about 1.72 g/cc to less than 2 g/cc, about 1.75
g/cc to less than 2 g/cc, or about 1.8 g/cc to less than 2
g/cc.
[0033] The nitrogen-doped diamond-like carbon film can have a
thickness of about 5 .ANG., about 10 .ANG., about 50 .ANG., about
100 .ANG., about 150 .ANG., about 200 .ANG., or about 300 .ANG. to
about 400 .ANG., about 500 .ANG., about 600 .ANG., about 700 .ANG.,
about 800 .ANG., about 1,000 .ANG., about 2,000 .ANG., about 3,000
.ANG., about 5,000 .ANG., about 6,000 .ANG., about 8,000 .ANG.,
about 10,000 .ANG., about 15,000 .ANG., about 20,000 .ANG., or
thicker. For example, the nitrogen-doped diamond-like carbon film
can have a thickness of about 5 .ANG. to about 20,000 .ANG., about
5 .ANG. to about 10,000 .ANG., about 5 .ANG. to about 5,000 .ANG.,
about 5 .ANG. to about 3,000 .ANG., about 5 .ANG. to about 2,000
.ANG., about 5 .ANG. to about 1,000 .ANG., about 5 .ANG. to about
500 .ANG., about 5 .ANG. to about 200 A, about 5 .ANG. to about 100
.ANG., about 5 .ANG. to about 50 .ANG., about 200 .ANG. to about
20,000 .ANG., about 200 .ANG. to about 10,000 .ANG., about 200
.ANG. to about 6,000 .ANG., about 200 .ANG. to about 5,000 .ANG.,
about 200 .ANG. to about 3,000 .ANG., about 200 .ANG. to about
2,000 .ANG., about 200 .ANG. to about 1,000 .ANG., about 200 .ANG.
to about 500 .ANG., about 600 .ANG. to about 3,000 .ANG., about 600
.ANG. to about 2,000 .ANG., about 600 .ANG. to about 1,500 .ANG.,
about 600 .ANG. to about 1,000 .ANG., about 600 .ANG. to about 800
.ANG., about 1,000 .ANG. to about 20,000 .ANG., about 1,000 .ANG.
to about 10,000 .ANG., about 1,000 .ANG. to about 5,000 .ANG.,
about 1,000 .ANG. to about 3,000 .ANG., about 1,000 .ANG. to about
2,000 .ANG., about 2,000 .ANG. to about 20,000 .ANG., or about
2,000 .ANG. to about 3,000 .ANG..
[0034] The nitrogen-doped diamond-like carbon film can have a
refractive index or n-value (n (at 633 nm)) of greater than 2, such
as about 2.1, about 2.2, about 2.3, about 2.4 or about 2.5 to about
2.6, about 2.7, about 2.8, about 2.9, or about 3. For example, the
nitrogen-doped diamond-like carbon film can have a refractive index
or n-value (n (at 633 nm)) of greater than 2 to about 3, greater
than 2 to about 2.8, greater than 2 to about 2.5, greater than 2 to
about 2.3, about 2.1 to about 3, about 2.1 to about 2.8, about 2.1
to about 2.5, about 2.1 to about 2.3, about 2.3 to about 3, about
2.3 to about 2.8, or about 2.3 to about 2.5.
[0035] The nitrogen-doped diamond-like carbon film can have an
extinction coefficient or k-value (K (at 633 nm)) of greater than
0.1, such as about 0.15, about 0.2, about 0.25, or about 0.3. For
example, the nitrogen-doped diamond-like carbon film can have an
extinction coefficient or k-value (K (at 633 nm)) of greater than
0.1 to about 0.3, greater than 0.1 to about 0.25, greater than 0.1
to about 0.2, greater than 0.1 to about 0.15, about 0.2 to about
0.3, or about 0.2 to about 0.25.
[0036] The nitrogen-doped diamond-like carbon film can have a
compressive stress of less than -600 MPa, such as about -10 MPa,
about -20 MPa, about -50 MPa, about -80 MPa, about -100 MPa, about
-150 MPa, about -200 MPa, about -250 MPa, about -275 MPa, or about
-300 MPa to about -325 MPa, about -350 MPa, about -375 MPa, about
-400 MPa, about -425 MPa, about -450 MPa, about -475 MPa, about
-500 MPa, about -550 MPa, about -580 MPa, or about -590 MPa. For
example, the nitrogen-doped diamond-like carbon film can have a
compressive stress of about -20 MPa to less than -600 MPa, about
-50 MPa to less than -600 MPa, about -100 MPa to less than -600
MPa, about -200 MPa to less than -600 MPa, about -250 MPa to less
than -600 MPa, about -300 MPa to less than -600 MPa, about -350 MPa
to less than -600 MPa, about -400 MPa to less than -600 MPa, about
-450 MPa to less than -600 MPa, about -500 MPa to less than -600
MPa, about -20 MPa to about -500 MPa, about -100 MPa to about -500
MPa, about -200 MPa to about -500 MPa, about -250 MPa to about -500
MPa, about -300 MPa to about -500 MPa, about -350 MPa to about -500
MPa, about -400 MPa to about -500 MPa, about -450 MPa to about -500
MPa, about -20 MPa to about -400 MPa, about -100 MPa to about -400
MPa, about -200 MPa to about -400 MPa, about -250 MPa to about -400
MPa, about -300 MPa to about -400 MPa, or about -350 MPa to about
-400 MPa.
[0037] The nitrogen-doped diamond-like carbon film can have an
elastic modulus of greater than 50 GPa or greater than 60 GPa, such
as about 65 GPa, about 70 GPa, about 75 GPa, about 90 GPa, about
100 GPa, about 125 GPa, or about 150 GPa to about 175 GPa, about
200 GPa, about 250 GPa, about 275 GPa, about 300 GPa, about 350
GPa, or about 400 GPa. For example, the nitrogen-doped diamond-like
carbon film can have an elastic modulus of greater than 60 GPa to
about 400 GPa, greater than 60 GPa to about 350 GPa, greater than
60 GPa to about 300 GPa, greater than 60 GPa to about 250 GPa,
greater than 60 GPa to about 200 GPa, greater than 60 GPa to about
150 GPa, greater than 60 GPa to about 125 GPa, greater than 60 GPa
to about 100 GPa, greater than 60 GPa to about 80 GPa, about 65 GPa
to about 400 GPa, about 65 GPa to about 350 GPa, about 65 GPa to
about 300 GPa, about 65 GPa to about 250 GPa, about 65 GPa to about
200 GPa, about 65 GPa to about 150 GPa, about 65 GPa to about 125
GPa, about 65 GPa to about 100 GPa, about 65 GPa to about 80 GPa,
about 80 GPa to about 400 GPa, about 80 GPa to about 350 GPa, about
80 GPa to about 300 GPa, about 80 GPa to about 250 GPa, about 80
GPa to about 200 GPa, about 80 GPa to about 150 GPa, about 80 GPa
to about 125 GPa, or about 80 GPa to about 100 GPa. In one or more
examples, the nitrogen-doped diamond-like carbon film can have the
aforementioned elastic modulus and have a thickness of about 600
.ANG..
[0038] In some embodiments, the nitrogen-doped diamond-like carbon
film is an underlayer for an extreme ultraviolet ("EUV")
lithography process. In some examples, the nitrogen-doped
diamond-like carbon film is an underlayer for an EUV lithography
process and has an spa hybridized carbon atom content of about 40%
to about 90% based on the total amount of carbon atoms in the film,
a density of greater than 1.5 g/cc to about 1.9 g/cc, and an
elastic modulus that is greater than or about 60 GPa to about 150
GPa or about 200 GPa.
[0039] FIG. 1A depicts a schematic illustration of a substrate
processing system 132 that can be used to perform nitrogen-doped
diamond-like carbon film deposition in accordance with embodiments
described herein. The substrate processing system 132 includes a
process chamber 100 coupled to a gas panel 130 and a controller
110. The process chamber 100 generally includes a top wall 124, a
sidewall 101 and a bottom wall 122 that define a processing volume
126. A substrate support assembly 146 is provided in the processing
volume 126 of the process chamber 100. The substrate support
assembly 146 generally includes an electrostatic chuck 150
supported by a stem 160. The electrostatic chuck 150 may be
typically fabricated from aluminum, ceramic, and other suitable
materials. The electrostatic chuck 150 may be moved in a vertical
direction inside the process chamber 100 using a displacement
mechanism (not shown).
[0040] A vacuum pump 102 is coupled to a port formed in the bottom
of the process chamber 100. The vacuum pump 102 is used to maintain
a desired gas pressure in the process chamber 100. The vacuum pump
102 also evacuates post-processing gases and by-products of the
process from the process chamber 100.
[0041] The substrate processing system 132 may further include
additional equipment for controlling the chamber pressure, for
example, valves (e.g., throttle valves and isolation valves)
positioned between the process chamber 100 and the vacuum pump 102
to control the chamber pressure.
[0042] A gas distribution assembly 120 having a plurality of
apertures 128 is disposed on the top of the process chamber 100
above the electrostatic chuck 150. The apertures 128 of the gas
distribution assembly 120 are utilized to introduce process gases
(e.g., deposition gas, dilution gas, carrier gas, purge gas) into
the process chamber 100. The apertures 128 may have different
sizes, number, distributions, shape, design, and diameters to
facilitate the flow of the various processing gases for different
process requirements. The gas distribution assembly 120 is
connected to the gas panel 130 that allows various gases to supply
to the processing volume 126 during processing. A plasma is formed
from the processing gas mixture exiting the gas distribution
assembly 120 to enhance thermal decomposition of the processing
gases resulting in the deposition of material on a surface 191 of
the substrate 190.
[0043] The gas distribution assembly 120 and the electrostatic
chuck 150 may form a pair of spaced apart electrodes in the
processing volume 126. One or more RF power source 140 provide a
bias potential through a matching network 138, which is optional,
to the gas distribution assembly 120 to facilitate generation of
plasma between the gas distribution assembly 120 and the
electrostatic chuck 150. Alternatively, the RF power source 140 and
the matching network 138 may be coupled to the gas distribution
assembly 120, the electrostatic chuck 150, or coupled to both the
gas distribution assembly 120 and the electrostatic chuck 150, or
coupled to an antenna (not shown) disposed exterior to the process
chamber 100. In one or more examples, the RF power source 140 may
produce power at a frequency of about 350 KHz, about 2 MHz, about
13.56 MHz, about 27 MHz, about 40 MHz, about 60 MHz, or about 100
MHz. In some examples, the RF power source 140 may provide power of
about 100 watts to about 3,000 watts at a frequency of about 50 kHz
to about 13.6 MHz. In other examples, the RF power source 140 may
provide power of about 500 watts to about 1,800 watts at a
frequency of about 50 kHz to about 13.6 MHz.
[0044] The controller 110 includes a central processing unit (CPU)
112, a memory 116, and a support circuit 114 utilized to control
the process sequence and regulate the gas flows from the gas panel
130. The CPU 112 may be of any form of a general-purpose computer
processor that may be used in an industrial setting. The software
routines can be stored in the memory 116, such as random access
memory, read only memory, floppy, or hard disk drive, or other form
of digital storage. The support circuit 114 is conventionally
coupled to the CPU 112 and may include cache, clock circuits,
input/output systems, power supplies, and the like. Bi-directional
communications between the controller 110 and the various
components of the substrate processing system 132 are handled
through numerous signal cables collectively referred to as signal
buses 118, some of which are illustrated in FIG. 1A.
[0045] FIG. 1B depicts a schematic cross-sectional view of another
substrate processing system 180 that can be used for the practice
of embodiments described herein. The substrate processing system
180 is similar to the substrate processing system 132 of FIG. 1A,
except that the substrate processing system 180 is configured to
flow processing gases from gas panel 130 across the surface 191 of
the substrate 190 via the sidewall 101. In addition, the gas
distribution assembly 120 depicted in FIG. 1A is replaced with an
electrode 182. The electrode 182 may be configured for secondary
electron generation. In one or more embodiments, the electrode 182
is a silicon-containing electrode.
[0046] FIG. 2 depicts a schematic cross-sectional view of the
substrate support assembly 146 used in the processing systems of
FIG. 1A and FIG. 1B that can be used for the practice of
embodiments described herein. Referring to FIG. 2, the
electrostatic chuck 150 may include a heater element 170 suitable
for controlling the temperature of a substrate 190 supported on an
upper surface 192 of the electrostatic chuck 150. The heater
element 170 may be embedded in the electrostatic chuck 150. The
electrostatic chuck 150 may be resistively heated by applying an
electric current from a heater power source 106 to the heater
element 170. The heater power source 106 may be coupled through an
RF filter 216. The RF filter 216 may be used to protect the heater
power source 106 from RF energy. The heater element 170 may be made
of a nickel-chromium wire encapsulated in a nickel-iron-chromium
alloy (e.g., INCOLOY.RTM. alloy) sheath tube. The electric current
supplied from the heater power source 106 is regulated by the
controller 110 to control the heat generated by the heater element
170, thus maintaining the substrate 190 and the electrostatic chuck
150 at a substantially constant temperature during film deposition.
The supplied electric current may be adjusted to selectively
control the temperature of the electrostatic chuck 150 to be about
-50.degree. C. to about 600.degree. C.
[0047] Referring to FIG. 1, a temperature sensor 172, such as a
thermocouple, may be embedded in the electrostatic chuck 150 to
monitor the temperature of the electrostatic chuck 150 in a
conventional manner. The measured temperature is used by the
controller 110 to control the power supplied to the heater element
170 to maintain the substrate at a desired temperature.
[0048] The electrostatic chuck 150 includes a chucking electrode
210, which may be a mesh of a conductive material. The chucking
electrode 210 may be embedded in the electrostatic chuck 150. The
chucking electrode 210 is coupled to a chucking power source 212
that, when energized, electrostatically clamps the substrate 190 to
the upper surface 192 of the electrostatic chuck 150.
[0049] The chucking electrode 210 may be configured as a monopolar
or bipolar electrode, or have another suitable arrangement. The
chucking electrode 210 may be coupled through an RF filter 214 to
the chucking power source 212, which provides direct current (DC)
power to electrostatically secure the substrate 190 to the upper
surface 192 of the electrostatic chuck 150. The RF filter 214
prevents RF power utilized to form plasma within the process
chamber 100 from damaging electrical equipment or presenting an
electrical hazard outside the chamber. The electrostatic chuck 150
may be fabricated from a ceramic material, such as aluminum nitride
or aluminum oxide (e.g., alumina). Alternately, the electrostatic
chuck 150 may be fabricated from a polymer, such as polyimide,
polyetheretherketone (PEEK), polyaryletherketone (PAEK), and the
like.
[0050] A power application system 220 is coupled to the substrate
support assembly 146. The power application system 220 may include
the heater power source 106, the chucking power source 212, a first
radio frequency (RF) power source 230, and a second RF power source
240. The power application system 220 may additionally include the
controller 110, and a sensor device 250 that is in communication
with the controller 110 and both of the first RF power source 230
and the second RF power source 240. The controller 110 may also be
utilized to control the plasma from the processing gas by
application of RF power from the first RF power source 230 and the
second RF power source 240 in order to deposit a layer of material
on the substrate 190.
[0051] As described above, the electrostatic chuck 150 includes the
chucking electrode 210 that may function in one aspect to chuck the
substrate 190 while also functioning as a first RF electrode. The
electrostatic chuck 150 may also include a second RF electrode 260,
and together with the chucking electrode 210, may apply RF power to
tune the plasma. The first RF power source 230 may be coupled to
the second RF electrode 260 while the second RF power source 240
may be coupled to the chucking electrode 210. A first matching
network and a second matching network may be provided for the first
RF power source 230 and the second RF power source 240,
respectively. The second RF electrode 260 may be a solid metal
plate of a conductive material as shown. Alternatively, the second
RF electrode 260 may be a mesh of conductive material.
[0052] The first RF power source 230 and the second RF power source
240 may produce power at the same frequency or a different
frequency. In one or more embodiments, one or both of the first RF
power source 230 and the second RF power source 240 may
independently produce power at a frequency from about 350 KHz to
about 100 MHz (e.g., 350 KHz, 2 MHz, 13.56 MHz, 27 MHz, 40 MHz, 60
MHz, or 100 MHz). In one or more embodiments, the first RF power
source 230 may produce power at a frequency of 13.56 MHz and the
second RF power source 240 may produce power at a frequency of 2
MHz, or vice versa. RF power from one or both of the first RF power
source 230 and second RF power source 240 may be varied in order to
tune the plasma. For example, the sensor device 250 may be used to
monitor the RF energy from one or both of the first RF power source
230 and the second RF power source 240. Data from the sensor device
250 may be communicated to the controller 110, and the controller
110 may be utilized to vary power applied by the first RF power
source 230 and the second RF power source 240.
[0053] In one or more embodiments, the electrostatic chuck 150 has
the chucking electrode 210 and an RF electrode separate from each
other, and the first RF bias can be applied to the RF electrode 260
and the second RF bias can be applied to the chucking electrode
210. In one or more examples, the first RF bias is provided at a
power of about 10 watts to about 3,000 watts at a frequency of
about 350 KHz to about 100 MHz and the second RF bias is provided
at a power of about 10 watts to about 3,000 watts at a frequency of
about 350 KHz to about 100 MHz. In other examples, the first RF
bias is provided at a power of about 2,500 watts to about 3,000
watts at a frequency of about 13.56 MHz and the second RF bias is
provided at a power of about 800 watts to about 1,200 watts at a
frequency of about 2 MHz.
[0054] In one or more embodiments, a deposition gas containing one
or more hydrocarbon compounds and one or more nitrogen dopant
compounds may be flowed or otherwise introduced into the processing
volume of the process chamber, such as a PE-CVD chamber. The
hydrocarbon compound and the nitrogen dopant compound may be
independently flowed or introduced into the processing volume. In
some examples, one or more substrates are positioned on an
electrostatic chuck in the process chamber. The electrostatic chuck
can have a chucking electrode and an RF electrode separate from
each other. A plasma may be ignited or otherwise generated at or
near the substrate (e.g., substrate level) by applying a first RF
bias to the RF electrode and a second RF bias to the chucking
electrode. The nitrogen-doped diamond-like carbon film is deposited
or otherwise formed on the substrate. In some embodiments, a
patterned photoresist layer may be deposited or otherwise formed
over the nitrogen-doped diamond-like carbon film, the
nitrogen-doped diamond-like carbon film is etched or otherwise
formed in a pattern corresponding with the patterned photoresist
layer, and the pattern is etched or otherwise formed into the
substrate.
[0055] In general, the following exemplary deposition process
parameters may be used to form the nitrogen-doped diamond-like
carbon film. The substrate temperature may range of about
-50.degree. C. to about 350.degree. C. (e.g., about -40.degree. C.
to about 100.degree. C., about 10.degree. C. to about 100.degree.
C., or about 10.degree. C. to about 50.degree. C.). The chamber
pressure may range from a chamber pressure of about 0.5 mTorr to
about 10 Torr (e.g., about 2 mTorr to about 50 mTorr, or about 2
mTorr to about 10 mTorr). The flow rate of the hydrocarbon compound
may be about 20 sccm to about 5,000 sccm (e.g., about 50 sccm to
about 1,000 sccm, about 100 sccm to about 200 sccm, or about 150
sccm to about 200 sccm). The flow rate of the nitrogen dopant
compound (e.g., N.sub.2) may be about 1 sccm to about 3,000 sccm
(e.g., about 5 sccm to about 500 sccm, about 10 sccm to about 150
sccm, or about 20 sccm to about 100 sccm). The flow rate of a
dilution gas or purge gas (e.g., He) may be about 1 sccm to about
3,000 sccm (e.g., about 5 sccm to about 500 sccm, about 10 sccm to
about 150 sccm, or about 20 sccm to about 100 sccm). The
nitrogen-doped diamond-like carbon film may be deposited to a
thickness of about 200 .ANG. and about 6,000 .ANG. (e.g., about 300
.ANG. to about 5,000 .ANG.; about 400 .ANG. to about 800 .ANG.;
about 2,000 .ANG. and about 3,000 .ANG., or about 5 .ANG. to about
200 .ANG.--depending on application). In one or more examples,
these process parameters provide examples of process parameters for
a 300 mm substrate in a deposition chamber commercially available
from Applied Materials, Inc. of Santa Clara, Calif.
[0056] FIG. 3 depicts a flow diagram of a method 300 for forming a
nitrogen-doped diamond-like carbon film on a film stack disposed on
a substrate in accordance with one embodiment of the present
disclosure. The nitrogen-doped diamond-like carbon film formed on a
film stack may be utilized, for example, as a hardmask to form
stair-like structures in the film stack. FIGS. 4A-4B are schematic
cross-sectional views illustrating a sequence for forming a
nitrogen-doped diamond-like carbon film on a film stack disposed on
a substrate according to the method 300. Although the method 300 is
described below with reference to a hardmask layer that may be
formed on a film stack utilized to manufacture stair-like
structures in the film stack for three dimensional semiconductor
devices, the method 300 may also be used to advantage in other
device manufacturing applications. Further, it should also be
understood that the operations depicted in FIG. 3 may be performed
simultaneously and/or in a different order than the order depicted
in FIG. 3.
[0057] The method 300 begins at operation 310 by positioning a
substrate, such as a substrate 402 depicted in FIG. 4A, into a
processing volume of a process chamber, such as the process chamber
100 depicted in FIG. 1A or FIG. 1B. The substrate 402 may be
substrate 190 depicted in FIG. 1A, FIG. 1B, and FIG. 2. The
substrate 402 may be positioned on an electrostatic chuck, for
example, the upper surface 192 of the electrostatic chuck 150. The
substrate 402 may be a silicon-based material or any suitable
insulating material or conductive material as needed, having a film
stack 404 disposed on the substrate 402 that may be utilized to
form a structure 400, such as stair-like structures, in the film
stack 404.
[0058] As shown in the embodiment depicted in FIG. 4A, the
substrate 402 may have a substantially planar surface, an uneven
surface, or a substantially planar surface having a structure
formed thereon. The film stack 404 is formed on the substrate 402.
In one or more embodiments, the film stack 404 may be utilized to
form a gate structure, a contact structure or an interconnection
structure in a front end or back end process. The method 300 may be
performed on the film stack 404 to form the stair-like structures
therein used in a memory structure, such as NAND structure. In one
or more embodiments, the substrate 402 may be a material such as
crystalline silicon (e.g., Si<100> or Si<111>), silicon
oxide, strained silicon, silicon germanium, doped or undoped
polysilicon, doped or undoped silicon substrates and patterned or
non-patterned substrates silicon on insulator (SOI), carbon doped
silicon oxides, silicon nitride, doped silicon, germanium, gallium
arsenide, glass, sapphire. The substrate 402 may have various
dimensions, such as 200 mm, 300 mm, 450 mm, or other diameter
substrates, as well as, rectangular or square panels. Unless
otherwise noted, embodiments and examples described herein are
conducted on substrates with a 200 mm diameter, a 300 mm diameter,
or a 450 mm diameter substrate. In the embodiment wherein a SOI
structure is utilized for the substrate 402, the substrate 402 may
include a buried dielectric layer disposed on a silicon crystalline
substrate. In one or more embodiments depicted herein, the
substrate 402 may be a crystalline silicon substrate.
[0059] In one or more embodiments, the film stack 404 disposed on
the substrate 402 may have a number of vertically stacked layers.
The film stack 404 may contain pairs including a first layer (shown
as 408a.sub.1, 408a.sub.2, 408a.sub.3, . . . , 408a.sub.n) and a
second layer (shown as 408b.sub.1, 408b.sub.2, 408b.sub.3, . . . ,
408b.sub.n) repeatedly formed in the film stack 404. The pairs
includes alternating first layer (shown as 408a.sub.1, 408a.sub.2,
408a.sub.3, . . . , 408a.sub.n) and second layer (shown as
408b.sub.1, 408b.sub.2, 408b.sub.3, . . . , 408b.sub.n) repeatedly
formed until desired numbers of pairs of the first layers and the
second layers are reached.
[0060] The film stack 404 may be a part of a semiconductor chip,
such as a three-dimensional memory chip Although three repeating
layers of first layers (shown as 408a.sub.1, 408a.sub.2,
408a.sub.3, . . . , 408a.sub.n) and second layers (shown as
408b.sub.1, 408b.sub.2, 408b.sub.3, . . . , 408b.sub.n) are shown
in FIGS. 4A-4B, it is noted that any desired number of repeating
pairs of the first and the second layers may be utilized as
needed.
[0061] In one or more embodiments, the film stack 404 may be
utilized to form multiple gate structures for a three-dimensional
memory chip. The first layers 408a.sub.1, 408a.sub.2, 408a.sub.3, .
. . , 408a.sub.n, formed in the film stack 404 may be a first
dielectric layer and the second layers 408b.sub.1, 408b.sub.2,
408b.sub.3, . . . , 408b.sub.n may be a second dielectric layer.
Suitable dielectric layers may be utilized to form the first layers
408a.sub.1, 408a.sub.2, 408a.sub.3, 408a.sub.n and the second layer
408b.sub.1, 408b.sub.2, 408b.sub.3, . . . , 408b.sub.n include
silicon oxide, silicon nitride, silicon oxynitride, silicon
carbide, silicon oxycarbide, titanium nitride, composite of oxide
and nitride, at least one or more oxide layers sandwiching a
nitride layer, and combinations thereof, among others. In one or
more embodiments, the dielectric layers may be a high-k material
having a dielectric constant greater than 4. Suitable examples of
the high-k materials include hafnium oxide, zirconium oxide,
titanium oxide, hafnium silicon oxide or hafnium silicate, hafnium
aluminum oxide or hafnium aluminate, zirconium silicon oxide or
zirconium silicate, tantalum oxide, aluminum oxide, aluminum doped
hafnium dioxide, bismuth strontium titanium (BST), and platinum
zirconium titanium (PZT), dopants thereof, or any combination
thereof.
[0062] In one or more examples, the first layers 408a.sub.1,
408a.sub.2, 408a.sub.3, 408a.sub.n are silicon oxide layers and the
second layers 408b.sub.1, 408b.sub.2, 408b.sub.3, 408b.sub.n are
silicon nitride layers or polysilicon layers disposed on the first
layers 408a.sub.1, 408a.sub.2, 408a.sub.3, 408a.sub.n. In one or
more embodiments, the thickness of first layers 408a.sub.1,
408a.sub.2, 408a.sub.3, 408a.sub.n may be controlled to be about 50
.ANG. to about 1,000 .ANG., such as about 500 .ANG., and the
thickness of the each second layers 408b.sub.1, 408b.sub.2,
408b.sub.3, 408b.sub.n may be controlled to be about 50 .ANG. to
about 1,000 .ANG., such as about 500 .ANG.. The film stack 404 may
have a total thickness of about 100 .ANG. to about 2,000 .ANG.. In
one or more embodiments, a total thickness of the film stack 404 is
about 3 microns to about 10 microns and can vary as technology
advances.
[0063] It is noted that the nitrogen-doped diamond-like carbon film
may be formed on any surfaces or any portion of the substrate 402
with or without the film stack 404 present on the substrate
402.
[0064] At operation 320, a chucking voltage is applied to the
electrostatic chuck and the substrate 402 clamped or otherwise
disposed on to the electrostatic chuck. In one or more embodiments,
where the substrate 402 is positioned on the upper surface 192 of
the electrostatic chuck 150, the upper surface 192 provides support
and clamps the substrate 402 during processing. The electrostatic
chuck 150 flattens the substrate 402 closely against the upper
surface 192, preventing backside deposition. An electrical bias is
provided to the substrate 402 via chucking electrode 210. The
chucking electrode 210 may be in electronic communication with the
chucking power source 212 that supplies a biasing voltage to the
chucking electrode 210. In one or more embodiments, the chucking
voltage is about 10 volts to about 3,000 volts, about 100 volts to
about 2,000 volts, or about 200 volts to about 1,000 volts.
[0065] During operation 320, several process parameters may be
regulated the process. In one embodiment suitable for processing a
300 mm substrate, the process pressure in the processing volume may
be maintained at about 0.1 mTorr to about 10 Torr (e.g., about 2
mTorr to about 50 mTorr; or about 5 mTorr to about 20 mTorr). In
some embodiments suitable for processing a 300 mm substrate, the
processing temperature and/or substrate temperature may be
maintained at about -50.degree. C. to about 350.degree. C. (e.g.,
about 0.degree. C. to about 50.degree. C.; or about 10.degree. C.
to about 20.degree. C.).
[0066] In one or more embodiments, a constant chucking voltage is
applied to the substrate 402. In some embodiments, the chucking
voltage may be pulsed to the electrostatic chuck 150. In other
embodiments, a backside gas may be applied to the substrate 402
while applying the chucking voltage to control the temperature of
the substrate. Backside gases can be or include helium, argon,
neon, nitrogen (N.sub.2), hydrogen (H.sub.2), or any combination
thereof.
[0067] At operation 330, a plasma is generated at the substrate,
such as adjacent the substrate or near the substrate level, by
applying a first RF bias to the electrostatic chuck. Plasma
generated at the substrate may be generated in a plasma region
between the substrate and the electrostatic chuck. The first RF
bias may be from about 10 watts to about 3,000 watts at a frequency
of about 350 KHz to about 100 MHz (e.g., about 350 KHz, about 2
MHz, about 13.56 MHz, about 27 MHz, about 40 MHz, about 60 MHz, or
about 100 MHz). In one or more embodiments, the first RF bias is
provided at a power of about 2,500 watts to about 3,000 watts at a
frequency of about 13.56 MHz. In one or more embodiments, the first
RF bias is provided to the electrostatic chuck 150 via the second
RF electrode 260. The second RF electrode 260 may be in electronic
communication with the first RF power source 230 that supplies a
biasing voltage to the second RF electrode 260. In one or more
embodiments, the bias power is about 10 watts to about 3,000 watts,
about 2,000 watts to about 3,000 watts, or about 2,500 watts to
about 3,000 watts. The first RF power source 230 may produce power
at a frequency of about 350 KHz to about 100 MHz (e.g., about 350
KHz, about 2 MHz, about 13.56 MHz, about 27 MHz, about 40 MHz,
about 60 MHz, or about 100 MHz).
[0068] In one or more embodiments, operation 330 further includes
applying a second RF bias to the electrostatic chuck. The second RF
bias may be from about 10 watts to about 3,000 watts at a frequency
of about 350 KHz to about 100 MHz (e.g., about 350 KHz, about 2
MHz, about 13.56 MHz, about 27 MHz, about 40 MHz, about 60 MHz, or
about 100 MHz). In some examples, the second RF bias is provided at
a power of about 800 watts to about 1,200 watts at a frequency of
about 2 MHz. In other examples, the second RF bias is provided to
the substrate 402 via the chucking electrode 210. The chucking
electrode 210 may be in electronic communication with second RF
power source 240 that supplies a biasing voltage to the chucking
electrode 210. In one or more examples, the bias power is about 10
watts to about 3,000 watts, about 500 watts to about 1,500 watts,
or about 800 watts to about 1,200 watts. The second RF power source
240 may produce power at a frequency of about 350 KHz to about 100
MHz (e.g., about 350 KHz, about 2 MHz, about 13.56 MHz, about 27
MHz, about 40 MHz, about 60 MHz, or about 100 MHz). In one or more
embodiments, the chucking voltage supplied in operation 320 is
maintained during operation 330.
[0069] In some embodiments, during operation 330, the first RF bias
is provided to the substrate 402 via the chucking electrode 210 and
the second RF bias may be provided to the substrate 402 via the
second RF electrode 260. In one or more examples, the first RF bias
is about 2,500 watts (about 13.56 MHz) and the second RF bias is
about 1,000 watts (about 2 MHz).
[0070] During operation 340, a deposition gas is flowed into the
processing volume 126 to form the nitrogen-doped diamond-like
carbon film on the film stack. The deposition gas may be flowed
from the gas panel 130 into the processing volume 126 either
through the gas distribution assembly 120 or via the sidewall 101.
The deposition gas contains one or more hydrocarbon compounds and
one or more nitrogen dopant compounds. The hydrocarbon compound can
be or include one, two, or more one hydrocarbon compounds in any
state of matter. Similarly, the nitrogen dopant compound can be or
include one, two, or more one nitrogen dopant compounds in any
state of matter. The hydrocarbon and/or nitrogen dopant compounds
can be any liquid or gas, but some advantages may be realized if
any of the precursors is vapor at room temperature in order to
simplify the hardware needed for material metering, control, and
delivery to the processing volume.
[0071] The deposition gas may further include an inert gas, a
dilution gas, a nitrogen-containing gas, an etchant gas or any
combination thereof. In one or more embodiments, the chucking
voltage supplied during operation 320 is maintained during
operation 340. In some embodiments, the process conditions
established during operation 320 and plasma formed during operation
330 are maintained during operation 340.
[0072] In one or more embodiments, the hydrocarbon compound is a
gaseous hydrocarbon or a liquid hydrocarbon. The hydrocarbon can be
or include one or more alkanes, one or more alkenes, one or more
alkynes, one or more aromatic, or any combination thereof. In some
examples, the hydrocarbon compound has a general formula
C.sub.xH.sub.y, where x has a range of 1 to about 20 and y has a
range of 1 to about 20. Suitable hydrocarbon compounds include, for
example, C.sub.2H.sub.2, C.sub.3H.sub.6, CH.sub.4, C.sub.4H.sub.8,
1,3-dimethyladamantane, bicyclo[2.2.1]hepta-2,5-diene
(2,5-norbornadiene), adamantine (C.sub.10H.sub.16), norbornene
(C.sub.7H.sub.10), or any combination thereof. In one or more
examples, ethyne is utilized due to formation of more stable
intermediate species, which allows more surface mobility.
[0073] The hydrocarbon compound can be or include one or more
alkanes (e.g., C.sub.nH.sub.2n+2, wherein n is from 1 to 20).
Suitable hydrocarbon compounds include, for example, alkanes such
as methane (CH.sub.4), ethane (C.sub.2H.sub.6), propane
(C.sub.3H.sub.8), butane (C.sub.4H.sub.10) and its isomer
isobutane, pentane (C.sub.5H.sub.12), hexane (C.sub.6H.sub.14) and
its isomers isopentane and neopentane, hexane (C.sub.6H.sub.14) and
its isomers 2-methylpentane, 3-methylpentane, 2,3-dimethylbutane,
and 2,2-dimethyl butane, or any combination thereof.
[0074] The hydrocarbon compound can be or include one or more
alkenes (e.g., C.sub.nH.sub.2n, wherein n is from 1 to 20).
Suitable hydrocarbon compounds include, for example, alkenes such
as ethylene, propylene (C.sub.3H.sub.6), butylene and its isomers,
pentene and its isomers, and the like, dienes such as butadiene,
isoprene, pentadiene, hexadiene, or any combination thereof.
Additional suitable hydrocarbons include, for example, halogenated
alkenes such as monofluoroethylene, difluoroethylenes,
trifluoroethylene, tetrafluoroethylene, monochloroethylene,
dichloroethylenes, trichloroethylene, tetrachloroethylene, or any
combination thereof.
[0075] The hydrocarbon compound can be or include one or more
alkynes (e.g., C.sub.nH.sub.2n-2, wherein n is from 1 to 20).
Suitable hydrocarbon compounds include, for example, alkynes such
as ethyne or acetylene (C.sub.2H.sub.2), propyne (C.sub.3H.sub.4),
butylene (C.sub.4H.sub.8), vinylacetylene, or any combination
thereof.
[0076] The hydrocarbon compound can be or include one or more
aromatic hydrocarbon compounds, such as benzene, styrene, toluene,
xylene, ethylbenzene, acetophenone, methyl benzoate, phenyl
acetate, phenol, cresol, furan, and the like, alpha-terpinene,
cymene, 1,1,3,3,-tetramethylbutylbenzene, t-butylether,
t-butylethylene, methyl-methacrylate, and t-butylfurfurylether,
compounds having the formula C.sub.3H.sub.2 and C.sub.5H.sub.4,
halogenated aromatic compounds including monofluorobenzene,
difluorobenzenes, tetrafluorobenzenes, hexafluorobenzene, or any
combination thereof.
[0077] The deposition gas contains one or more nitrogen dopant
compounds. Exemplary nitrogen dopant compounds can be or include
dinitrogen (N.sub.2), atomic nitrogen, ammonia, hydrazine,
methylhydrazine, dimethlyhydrazine, t-butylhydrazine,
phenylhydrazine, azoisobutane, ethylazide, pyridine, derivatives
thereof, abducts thereof, or any combination thereof. In one or
more embodiments, the deposition gas further contains one or more
dilution gases, one or more carrier gases, and/or one or more purge
gases. Suitable dilution gases, carrier gases, and/or purge gases
such as helium (He), argon (Ar), xenon (Xe), hydrogen (H.sub.2),
nitrogen (N.sub.2), ammonia (NH.sub.3), nitric oxide (NO), or any
combination thereof, among others, may be co-flowed or otherwise
supplied with the deposition gas into the processing volume 126.
Argon, helium, and/or nitrogen can be used to control the density
and deposition rate of the nitrogen-doped diamond-like carbon film.
In some cases, the addition of N.sub.2 and/or NH.sub.3 can be used
to control the hydrogen ratio of the nitrogen-doped diamond-like
carbon film, as discussed below. Alternatively, dilution gases may
not be used during the deposition.
[0078] In some embodiments, the deposition gas further contains an
etchant gas. Suitable etchant gases can be or include chlorine
(Cl.sub.2), fluorine (F.sub.2), hydrogen fluoride (HF), carbon
tetrafluoride (CF.sub.4), nitrogen trifluoride (NF.sub.3), or any
combination thereof. Not to be bound by theory, but it is believed
that the etchant gases selectively etch sp.sup.2 hybridized carbon
atoms from the film thus increasing the fraction of sp.sup.3
hybridized carbon atoms in the film, which increases the etch
selectivity of the film.
[0079] In one or more embodiments, after the nitrogen-doped
diamond-like carbon film 412 is formed on the substrate during
operation 340, the nitrogen-doped diamond-like carbon film 412 is
exposed to hydrogen radicals. In some embodiments, the
nitrogen-doped diamond-like carbon film is exposed to hydrogen
radicals during the deposition process of operation 340. In other
embodiments, the hydrogen radicals formed in an RPS and delivered
to the processing region. Not to be bound by theory, but it is
believed that exposing the nitrogen-doped diamond-like carbon film
to hydrogen radicals leads to selective etching of sp.sup.2
hybridized carbon atoms thus increasing the sp.sup.3 hybridized
carbon atom fraction of the film, thus increasing the etch
selectivity.
[0080] At operation 350, after the nitrogen-doped diamond-like
carbon film 412 is formed on the substrate, the substrate is
de-chucked. During operation 350, the chucking voltage is
turned-off. The reactive gases are turned-off and optionally purged
from the processing chamber. In one or more embodiments, the RF
power is reduced (e.g., about 200 watt) during operation 350.
Optionally, the controller 110 monitors impedance change to
determine whether electrostatic charges are dissipated to ground
through the RF path. Once the substrate is de-chucked from the
electrostatic chuck, the remaining gases are purged from the
processing chamber. The processing chamber is pumped down and the
substrate is moved up on the lift pins and transferred out of
chamber.
[0081] FIG. 5 depicts a flow diagram of a method 500 of using a
nitrogen-doped diamond-like carbon film in accordance with one or
more embodiments described and discussed herein. After the
nitrogen-doped diamond-like carbon film 412 is formed on the
substrate, the nitrogen-doped diamond-like carbon film 412 may be
utilized in an etching process as a patterning mask to form a
three-dimensional structure, such as a stair like structure. The
nitrogen-doped diamond-like carbon film 412 may be patterned using
a standard photoresist patterning techniques. At operation 510, a
patterned photoresist (not shown) may be formed over the
nitrogen-doped diamond-like carbon film 412. At operation 520, the
nitrogen-doped diamond-like carbon film 412 may be etched in a
pattern corresponding with the patterned photoresist layer followed
by etching the pattern into the substrate 402 at operation 530. At
operation 540, material may be deposited into the etched portions
of the substrate 402. At operation 550, the nitrogen-doped
diamond-like carbon film 412 may be removed using a solution
containing hydrogen peroxide and sulfuric acid. One exemplary
solution containing hydrogen peroxide and sulfuric acid is known as
Piranha solution or Piranha etch. The nitrogen-doped diamond-like
carbon film 412 may also be removed using etch chemistries
containing oxygen and halogens (e.g., fluorine or chlorine), for
example, Cl.sub.2/O.sub.2, CF.sub.4/O.sub.2,
Cl.sub.2/O.sub.2/CF.sub.4. The nitrogen-doped diamond-like carbon
film 412 may be removed by a chemical mechanical polishing (CMP)
process.
Extreme Ultraviolet ("EUV") Patterning Schemes
[0082] The choice of underlayer is critical to preventing
nanofailures (e.g., bridging defects and spacing defects) in
semiconductor devices when using metal-containing photoresists in
extreme ultraviolet ("EUV") patterning schemes. Conventional
underlayers for EUV patterning (lithography) schemes are spin on
carbon (SOC) materials. However, during patterning, metals such as
tin, for example, diffuse through the SOC material leading to
nanofailures in the semiconductor devices. Such nanofailures act to
reduce, degrade, and hamper semiconductor performance.
[0083] The high-density carbon films described herein, on the other
hand, have superior film qualities such as improved hardness and
density. Such hardness and density allow the high-density carbon
film to act as a stronger barrier against metal infiltration and to
prevent and at a minimum, reduce nanofailures to a greater extent
than the conventional SOC films. In one or more embodiments, a
nitrogen-doped diamond-like carbon film for use as an underlayer
for an extreme ultraviolet ("EUV") lithography process is
provided.
[0084] In one or more embodiments, a nitrogen-doped diamond-like
carbon film for use as an underlayer for an EUV lithography process
can be any film described herein. The nitrogen-doped diamond-like
carbon film can have an sp.sup.3 hybridized carbon atom content of
about 40% to about 90% based on the total amount of carbon atoms in
the nitrogen-doped diamond-like carbon film, a compressive stress
of about -20 MPa to less than -600 MPa, about -150 MPa to less than
-600 MPa, or about -200 MPa to less than -600 MPa, such as about
-225 MPa to about -500 MPa or about -250 MPa to about -400 MPa, an
elastic modulus of greater than 60 GPa to about 200 GPa or greater
than 60 GPa to about 150 GPa, and a density of greater than 1.5
g/cc to about 2.1 g/cc, such as about 1.55 g/cc to less than 2
g/cc, for example, about 1.6 g/cc to about 1.8 g/cc, about 1.65
g/cc to about 1.75 g/cc, or about 1.68 g/cc to about 1.72 g/cc.
[0085] Thus, methods and apparatuses for forming a hardmask layer,
which is or contains a nitrogen-doped diamond-like carbon film,
which may be utilized to form stair-like structures for
manufacturing three-dimensional stacking of semiconductor devices
are provided. By utilization of the nitrogen-doped diamond-like
carbon film as a hardmask layer with desired robust film properties
and etching selectivity, an improved dimension and profile control
of the resultant structures formed in a film stack may be obtained
and the electrical performance of the chip devices may be enhanced
in applications for three-dimensional stacking of semiconductor
devices.
[0086] In summary, some of the benefits of the present disclosure
provide a process for depositing or otherwise forming
nitrogen-doped diamond-like carbon films on a substrate. Typical
PE-CVD hardmask films have a very low percent of hybridized
sp.sup.3 atoms and hence low modulus and etch selectivity. In some
embodiments described herein, low process pressures (less than 1
Torr) and bottom driven plasma enables fabrication of doped films
with about 60% or greater hybridized sp.sup.3 atoms, which results
in an improvement in etch selectivity relative to previously
available hardmask films. In addition, some of the embodiments
described herein are performed at low substrate temperatures, which
enable the deposition of other dielectric films at much lower
temperatures than currently possible, opening up applications with
low thermal budget that could not be currently addressed by CVD.
Additionally, some of the embodiments described herein may be used
as an underlayer for an EUV lithography process.
[0087] While the foregoing is directed to embodiments of the
disclosure, other and further embodiments may be devised without
departing from the basic scope thereof, and the scope thereof is
determined by the claims that follow. All documents described
herein are incorporated by reference herein, including any priority
documents and/or testing procedures to the extent they are not
inconsistent with this text. As is apparent from the foregoing
general description and the specific embodiments, while forms of
the present disclosure have been illustrated and described, various
modifications can be made without departing from the spirit and
scope of the present disclosure. Accordingly, it is not intended
that the present disclosure be limited thereby. Likewise, the term
"comprising" is considered synonymous with the term "including" for
purposes of United States law. Likewise whenever a composition, an
element or a group of elements is preceded with the transitional
phrase "comprising", it is understood that we also contemplate the
same composition or group of elements with transitional phrases
"consisting essentially of," "consisting of", "selected from the
group of consisting of," or "is" preceding the recitation of the
composition, element, or elements and vice versa.
[0088] Certain embodiments and features have been described using a
set of numerical upper limits and a set of numerical lower limits.
It should be appreciated that ranges including the combination of
any two values, e.g., the combination of any lower value with any
upper value, the combination of any two lower values, and/or the
combination of any two upper values are contemplated unless
otherwise indicated. Certain lower limits, upper limits and ranges
appear in one or more claims below.
* * * * *